Comparison of rival metabolic syndrome classifications against pathophysiological markers in renal transplant...

Metabolic syndrome posttransplantation is associated with adverse outcomes. Diagnostic controversy exists, with adult treatment panel (ATP) III and International Diabetes Federation (IDF) classifications differing in prerequisite requirement of central obesity. In addition, correlation between classifications and putative pathophysiological mechanisms posttransplantation are lacking and may be obscured by immunosuppressants. We compared the two classifications against insulin resistance, subclinical inflammation, and central obesity in renal transplant recipients.

Ninety-six sets of metabolic investigations were analyzed in a cohort of 58 nondiabetic renal transplant recipients. Mathematical model analysis of the frequently sampled, intravenous glucose tolerance test was performed to determine insulin sensitivity (10(-5)min(-1)/mU/mL). We used waist/hip ratio as a surrogate for central obesity and C-reactive protein (mg/L) for subclinical inflammation, respectively. Clinical/biochemical parameters were also assessed at each metabolic investigation.

Fifty-nine percent of the study cohort was classed with metabolic syndrome using ATP III criteria, but only 43% using IDF criteria. IDF-classified recipients were more likely to have insulin resistance (3.7 vs. 4.9, P=0.034), raised waist/hip ratio (0.96 vs. 0.88, P<0.001), and elevated C-reactive protein (7.2 vs. 2.9, P=0.004) than those without the syndrome. Using ATP III criteria, there was a significant association with waist/hip ratio alone (syndrome vs. no syndrome, 0.95 vs. 0.86, P<0.001). Recipients with IDF-classified metabolic syndrome had significantly lower estimated glomerular filtration rate (mL/min) compared with those without (61.8 vs. 73.6, P=0.015).

The IDF-classified metabolic syndrome is superior to ATP III for association with pathophysiological mechanisms posttransplantation.